Diagnostic and Interventional Radiology
Chest Imaging - Original Article

Diffusion-weighted MRI in the characterization of pleural effusions

1.

Departments of Radiology, Kocaeli University School of Medicine, Kocaeli, Turkey

2.

Departments of Radiology, Kocaeli University School of Medicine, Kocaeli, Turkey

3.

From the Departments of Pulmonary Diseases, Kocaeli University School of Medicine, Kocaeli, Turkey

4.

From the Departments of Pediatric Surgery, Kocaeli University School of Medicine, Kocaeli, Turkey

Diagn Interv Radiol 2009; 15: 13-18
Read: 558 Downloads: 486 Published: 03 September 2019

Abstract

PURPOSE
To evaluate the value of diffusion-weighted imaging (DWI) in the differential diagnosis of pleural effusions.

 

MATERIALS AND METHODS
58 pleural effusions (21 transudative, 37 exudative) were included in this prospective study. Single-shot echo-planar spin echo DWI was performed with two b factors (500 and 1000 s/mm2), and apparent diffusion coefficients (ADCs) were calculated. On diffusion- weighted (DW) trace images, signal intensity (SI) of the pleural effusions was visually compared to the SI of the paraspinal muscles with the use of a 3-point scale: 0: isointense, 1: moderately hyperintense, 2: significantly hyperintense. For quantitative evaluation, effusion- to-paraspinal muscle SI ratios, and ADCs of the effusions were compared between the groups.

 

RESULTS
On visual evaluation, most of the transudative effusions were isointense, while most of the exudative effusions were hyperintense on DWI with b factors of 500 and 1000 s/mm2. Quantitatively, with a b factor of 500 and 1000 s/mm2, effusion-to-paraspinal muscle SI ratios of the exudative effusions were significantly higher than those of transudative effusions. The ADCs of the exudative effusions were significantly lower than those of transudative effusions (mean ADC was 3.3 × 10-3 ± 0.7 mm2/s for exudative effusions, and 3.7 × 10-3 ± 0.3 mm2/s for transudative effusions). Setting the cutoff value at 3.6 × 10-3, ADC had a sensitivity of 71% and a specificity of 63% for differentiating transudative from exudative effusions.

 

CONCLUSION
DWI may help in the differential diagnosis of pleural effusions.

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